This disclosure relates to wireless communications.
Wireless communication devices can use one or more wireless communication technologies such as orthogonal frequency division multiplexing (OFDM) or code division multiple access (CDMA). In an OFDM based wireless communication system, a data stream is split into multiple data substreams. Such data substreams are sent over different OFDM subcarriers, which can be referred to as tones or frequency tones. Various examples of wireless communication devices include mobile phones, smart phones, wireless routers, wireless hubs, base stations, and access points. In some cases, wireless communication electronics are integrated with data processing equipment such as laptops, personal digital assistants, and computers.
Wireless communication systems provide mechanisms for data retransmission such as automatic repeat request (ARQ) and hybrid ARQ (HARQ). In ARQ, error detection (ED) information bits, e.g., cyclic redundancy check (CRC) bits or checksum bits, are included in a data transmission. A wireless communication device can use error detection bits to detect one or more errors in a decoded version of a received message. In HARQ, error correction bits such as forward error correction (FEC) bits are included in a data transmission. A wireless communication device can use error correction bits to correct one or more errors in a decoded version of a received message. A data transmission can include FEC bits and error detection bits. In some implementations, FEC bits provide error detection capabilities. A wireless communication device can use a coding technique such as Reed-Solomon coding, convolutional coding, or turbo coding to encode and decode data. Encoding data may compensate for noise on a wireless communication channel.